Does Your Fish Tank Need An Air Pump?


In most fish tanks there is an air pump blowing the water towards the surface. It might look beautiful to have the water moving and there are some benefits of having it too. But do you really need an air pump?

An air pump is not necessary to have for a fish tank to function. If you need to oxygenate the water, or if you have a filter in your fish tank you need an air pump. If you don’t have an air pump you need a lot of plants providing oxygen and filtration in your fish tank.

If you don’t need an air pump, then why do most fish tanks have one? There are some benefits to having an air pump in your fish tank. Some benefits could be a make it or break it for your fish tank.

Why you have an air pump in a fish tank?

In total there are two main reasons why you should have an air pump in your fish tank. At first, the air pump is helping with oxygenating the water and secondly, the air pump is helping to pull the water through the filter helping to filter the water.

How an air pump is helping with oxygenation

The air pump is not pumping the air as the name suggests it does. It does, however, provide oxygen to the water.

The fish in your fish tank needs oxygen to be able to breathe. Most fish are picking up the oxygen from the water by sieving the water through its gills.

For them to be able to do it, you need the oxygen molecules inside the water.

What the air pump does is that you aim it towards the surface. You see, the pump is sucking the water from the fish tank and send it out a nozzle.

The water flowing out from the nozzle will break the surface tension which makes oxygen from the air above the water dissolve into the water.

The more the surface moves, the more oxygen you will get into the water and your water will get more oxygenated.

An air stone oxygenates the water the same way. In this case, the bubbles coming from the air stone is containing oxygen but it doesn’t dissolve into the water.

Instead, the bubbles are breaking the surface tension when they pop at the surface and thus letting the oxygen dissolve into the water.

An air pump is a big help oxygenate the water if you have problems with the water having too little oxygen. It’s not necessary though since an air stone is doing the same thing to oxygenate the water.

How an air pump is filtering the water

The air pump is pulling the water from the fish tank and out through a nozzle back into the fish tank. This is achieved due to a propeller at the bottom of the pump rotating, creating a suction pulling in the water.

But the water is not only going through the air pump and back out. The water also goes through a filter.

The filter will filter out debris from the water, also getting sucked in with the water preventing the debris to get stuck in the air pump and destroying the motor of the pump.

Without the filter, the air pump will not be lasting for long. Dead leaves and other organic material will clog up the pump quite quickly.

The filter also houses a lot of the beneficial bacteria you have in your fish tank. The bacteria are breaking down organic matter reducing the risk of ammonia and nitrite and that is making it safer for the fish.

By pulling the water through a filter you reduce the risk of the air pump breaking for you and you also help with making the water quality better and safer for your fish.

How do you oxygenate a tank without an air pump?

There are two different ways of oxygenating a fish tank without having an air pump. Firstly is with an air stone and secondly, it is with plants.

Oxygenate your fish tank with an air stone

A common way of oxygenating the water is with an air stone.

The air stone is not as effective as the air pump in oxygenating the water. It’s a common misconception that the bubbles themselves are oxygenating the water.

That is not the case. It’s when the bubbles are breaking the surface tension the oxygen gets dissolves into the water.

The bubbles themselves are containing oxygen but are not dissolved into the water.

The air pump has more water flow thus making it more effective in breaking the surface tension and letting the oxygen dissolve.

The air stone is prettier than the air pump in most cases. A lot of people like the way the small tiny bubbles are moving up to the surface. It gives more life to the fish tank.

But from a functionality perspective, the bubbles are less effective than the air pump in providing the water with oxygen. Also, the air stone doesn’t have any filter which is a downside compared to an air pump.

You probably still need an air pump while having an air stone due to the filtration benefits.

Oxygenate your fish tank with plants

A common practice in aquascaping, which is the art of making planted landscapes under the water in tanks, is to not have any air pump moving the water around. It will destroy most looks of aquascaping.

Instead, the plants are providing the water with oxygen. Now, not all aquascapes have fish in them but some do. The plants themselves don’t need oxygen, they produce it.

That’s exactly how a planted tank will produce oxygen for the water. The plants in a fish tank (or an aquascape) will use carbon dioxide dissolved in the water and use the light to utilize the photosynthesis.

A rest product of photosynthesis is oxygen which most of the time will get dissolved into the water. Sometimes if the water is well oxygenating you will see small bubbles being formed on the leaves of the plants.

Those bubbles are the oxygen the plants are producing.

The plants will also do some filtration of the water. The plants need nutrition that they will get from the water. This will also prevent algae from growing due to increased competition from the plants.

If you want to read more about algae I have a guide on why you get algae and what to do to prevent them from growing.

The filtration from plants is most of the time not sufficient enough if you have fish in your planted aquarium.

The waste from the fish needs to be broken down in order not to get toxic for the fish living inside the fish tank.

The bacteria breaking down waste lives everywhere in the tank but are more concentrated inside a filter so, the water quality will be safer if you have a filter while keeping fish due to the more effective breakdown of waste.

When you have a filter, you need a pump dragging the water through the filter.

So, if you keep fish in your planted fish tank it’s best to have an air pump to help with the filtration. If you have very few or no fish at all, you don’t need to have an air pump to help with the filtration, the bacteria living in the fish tank will make the breakdown for you.

It’s recommended for the water quality to have a filter and therefore also an air pump when having a planted fish tank with fish.

Can fish live without an air pump?

All fish can live without an air pump. It’s not suitable for all fish to live without an air pump. Some fish are used to live in strong currents and should have a strong current in your fish tank.

A strong current is achieved with a strong air pump.

Almost all fish need the water to be well oxygenated which is also easiest achieved with an air pump.

Type of fishNeeding well-oxygenated waterPreferring strong current from the air pump?
Betta fishNoNo
Neon TetraYesYes
GuppiesYesNo
GouramiNoNo
AngelfishYesYes
Corydora catfishYesYes
RasboraYesNo
DaniosYesNo
Malawi cichlidsYesYes
Common fish and their needs

As you see in the table, almost all fish needs the water to be well-oxygenated. But not all need the water flow from the pump.

Gourami and Betta fish are the only ones on this table that don’t need well-oxygenated water.

That’s because they are labyrinth fish which means that they have a special organ making them able to gram air from the surface and thus not need the oxygen in the water for them to be able to breathe.

It’s easier to keep labyrinth fish in a fish tank without an air pump due to them being able to get the air from the surface. But it’s still possible to keep other fish without an air pump too.

If keeping other types of fish that don’t need strong current, you can still oxygenate the water with a lot of plants producing oxygen.

If your fish need strong current, as Malawi cichlids do, you need a strong air pump to make the environment as good as possible for them.

How do I know my fish gets enough oxygen?

One of the main reasons to have an air pump is to dissolve oxygen in the water for the fish to be able to get oxygen through the gills. So, if the water lacks oxygen the fish will have a hard time getting their oxygen. When thinking about if you need an air pump or not you should take a look at if your fish get enough oxygen.

But, how do you see that your fish gets enough oxygen?

You look at the gills and how they behave. If the gills are moving fast, it’s a sign of them having a hard time getting oxygen.

It’s the same thing as when we gasp for breath. We need to increase our oxygen intake so we breathe more heavily.

Another sign of fish needing more oxygen is if they swim very high up in the fish tank and grabbing air from the surface.

The fish can grab air from the surface but it’s not optimal for them since they run the risk of getting sick and getting problems with their swim bladder.

If you see any of these two signs in your fish, you should absolutely consider getting an air pump if you don’t have one.

If you already have an air pump, if possible, increase the flowrate to break the surface tension more effectively. If it’s not possible to increase the flow, move the nozzle more towards the surface so there will be more movement at the surface, thus getting the water more oxygenated.

Is it necessary to have an air pump in planted tanks?

In planted tanks, it’s not as important to have an air pump as in tanks without plants. That’s because the plants will provide the water with oxygen and also filter the water.

The plants utilize photosynthesis which produces oxygen and releases it into the water.

Photosynthesis is the act of the plants grabbing carbon dioxide (CO2) from the water and using the light to convert it into energy for the plant and oxygen. The oxygen is a rest product for the plant and it releases it into the environment.

That oxygen gets dissolved into the water straight away. But, sometimes you could see small air bubbles rising from the leaves of the plant and that is oxygen bubbles.

That is a sign of well-oxygenated water.

When having a lot of plants it’s not necessary to have an air pump to get oxygen into the water, but if you have fish in your tank you need filtration.

While plants do filter some of the water, they will not filter everything so while keeping fish it’s necessary to have a filter and with the filter, you need something bringing the water through it and that’s a job for the air pump.

It’s most common to have an air pump, although not needed while having a lot of plants. That’s because the filtration will be so much better and the water quality will be a lot better for the inhabitants in the fish tank.

When having CO2 added into the water

Some tanks with a lot of plants, or if you keep more demanding plants, you could add CO2 into the water.

If adding CO2 into the water you should not have an air pump pumping all the time. The air pump will work against the CO2 by adding surface movement and adding oxygen instead which makes the CO2 less effective.

You could still have an air pump but have it on only at night when the light is off. If the light is off, the plants are not able to utilize photosynthesis and they will not consume CO2.

Then it’s a good time to add oxygen into your water, for your fish.

If you don’t have fish and are adding CO2, you should not have an air pump at all. That’s because the added oxygen is not providing anything beneficial, only hinder the CO2.

And you don’t really need any filtration when not having fish either.

Andreas

I have been a fish keeper a big part of my life. During the years I have gathered and searched a lot of information about fish keeping and here, on the website, is where I share that information to help you with your fish keeping. I want to provide the information that I didn't get when I had a question about my fish tank.

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